scholarly journals In-Flight Calibration and Performance of the OSIRIS-REx Visible and IR Spectrometer (OVIRS)

2018 ◽  
Vol 10 (9) ◽  
pp. 1486 ◽  
Author(s):  
Amy Simon ◽  
Dennis Reuter ◽  
Nicolas Gorius ◽  
Allen Lunsford ◽  
Richard Cosentino ◽  
...  

Performance of the Origins, Spectral Interpretation, Resource Identification, Security–Regolith Explorer (OSIRIS-REx) Visible and InfraRed Spectrometer (OVIRS) instrument was validated, showing that it met all science requirements during extensive thermal vacuum ground testing. Preliminary instrument radiometric calibration coefficients and wavelength mapping were also determined before instrument delivery and launch using NIST-traceable sources. One year after launch, Earth flyby data were used to refine the wavelength map by comparing OVIRS spectra with atmospheric models. Near-simultaneous data from other Earth-orbiting satellites were used to cross-calibrate the OVIRS absolute radiometric response, particularly at visible wavelengths. Trending data from internal calibration sources and the Sun show that instrument radiometric performance has been stable to better than 1% in the 18 months since launch.

2017 ◽  
Vol 16 (3) ◽  
pp. 303-321
Author(s):  
Elena Precourt ◽  
Henry Oppenheimer

Purpose The purpose of this paper is to examine analyst followings of firms starting from one year prior to their filing for Chapter 11 and as the firms progress through bankruptcy proceedings with a focus on firms receiving “Hold” or better recommendations. The authors attempt to answer questions such as what the common characteristics of the firms receiving stronger than expected recommendations one year prior to filing for bankruptcy reorganization or while in bankruptcy are, and how the market reacts to the issuance of stronger ratings for those firms. Design/methodology/approach The authors design various regressions and apply them to a total of 2,754 sell-side analyst recommendations and 325 firms that are either approaching bankruptcy filing or in the process of reorganizing. In each analysis, the authors control for several firm and performance characteristics. Findings The authors find that the probability of securing stronger ratings is higher for small firms and for those followed by a greater number of analysts than for large firms and firms followed by fewer analysts. The market becomes more skeptical of optimistic evaluations closer to the date of bankruptcy filing (perhaps reflecting some anticipation) and reacts more positively to rating upgrades issued during bankruptcy protection than to the upgrades issued before the bankruptcy filing. Research limitations/implications The conclusions are based on the analysis of analyst recommendations issued shortly before Chapter 11 filings and during bankruptcy proceedings. The conclusions could be strengthened by further analysis of firms’ post-bankruptcy recovery and performance and examination of analyst recommendations issued for the firms after they emerge from Chapter 11.. Practical implications Analyst security ratings that are more positive than expected are perhaps the result of superior expertise and access to private information. During bankruptcy proceedings, when information disclosure is limited, investors could greatly benefit from reports issued by security analysts. Originality/value This study contributes to the literature in a number of ways. First, the authors contribute to the literature on the analyst ratings of firms in distress by considering the period between bankruptcy filing and emergence, while the existing literature provides analysis of pre-bankruptcy recommendations and forecasts. Second, the authors focus on better than expected ratings rather than all types of ratings as the firms approach bankruptcy filings and proceed through reorganization. Finally, they evaluate how investors react to stronger than expected analyst ratings.


2020 ◽  
Vol 644 ◽  
pp. A148 ◽  
Author(s):  
A. A. Simon ◽  
H. H. Kaplan ◽  
E. Cloutis ◽  
V. E. Hamilton ◽  
C. Lantz ◽  
...  

Context. The NASA Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission has obtained thousands of spectra of asteroid (101955) Bennu with the OSIRIS-REx Visible and InfraRed Spectrometer. Aims. We present a spectral search for minor absorption bands and determine compositional variations on the surface of Bennu. Methods. Reflectance spectra with low and high spatial resolutions were analyzed for evidence of weak absorption bands. Spectra were also divided by a global average spectrum to isolate unique spectral features, and variations in the strongest band depths were mapped on a surface shape model. The global visible to near-IR spectrum of Bennu shows evidence of several weak absorption bands with depths of a few percent. Results. Several observed bands are consistent with phyllosilicates, and their distribution correlates with the stronger 2.74-μm hydration band. A 0.55-μm band is consistent with iron oxides and is deepest in the spectrally reddest areas on Bennu. The presence of hydrated phyllosilicates and iron oxides indicates substantial aqueous alteration in Bennu’s past. Conclusions. Bennu’s spectra are not identical to a limited set of carbonaceous chondrite spectra, possibly due to compositional properties and spatial scale differences; however, returned samples should contain a mixture of common chondrite materials.


2019 ◽  
Vol 3 (1) ◽  
pp. 186-192
Author(s):  
Yudi Wibawa

This paper aims to study for accurate sheet trim shower position for paper making process. An accurate position is required in an automation system. A mathematical model of DC motor is used to obtain a transfer function between shaft position and applied voltage. PID controller with Ziegler-Nichols and Hang-tuning rule and Fuzzy logic controller for controlling position accuracy are required. The result reference explains it that the FLC is better than other methods and performance characteristics also improve the control of DC motor.


2019 ◽  
pp. 58-62
Author(s):  
Vlad Stegariu ◽  
Simona Andreea Popușoi ◽  
Beatrice Abălașei ◽  
Nicolae Lucian Voinea ◽  
Ioan Stelescu ◽  
...  

Chess playing has a significant role in participants’ resources allocation, both at a psychological level, but mostly concerning the cognitive resources. The aim of the present study was to examine the effect of chess playing on the intellectual development of primary-class students. 67 children were tested using the Raven Standard Progressive Matrices and were distributed in three different groups according to their experience with chess, namely: the control group (formed by students with no experience with chess playing), the beginners group (students with less than one year in chess playing training) and the advanced group (children with more than two years experience with chess). Results indicated that chess playing had a significant effect on the SPM performance, indicating that those in the advanced group performed significantly better than those in the control or in the beginners group. Conclusions of this study tap into the benefits of playing chess with a focus on the children’s’ cognitive development.


Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.


2021 ◽  
pp. 1932202X2110186
Author(s):  
Sarah Fierberg Phillips ◽  
Brett Lane

The U.S. economy requires a highly educated workforce, yet too few black, Latino, and low-income students attend, persist, and graduate from college. The present study examines the college outcomes of participants in a model Advanced Placement® (AP) intervention to shed light on its effectiveness and determine whether improving AP participation and performance is a promising strategy for closing persistent racial/ethnic and socioeconomic disparities in college outcomes. Findings suggest the college outcomes of program participants are better than those of similar students statewide while also highlighting variation within and across subgroups. At the same time, they confirm that AP participation and performance predict college outcomes and suggest that improving AP participation and performance among low-income white, black, and Latino students could be a useful strategy for closing persistent racial/ethnic and socioeconomic disparities in college outcomes.


2000 ◽  
Vol 78 (2) ◽  
pp. 320-326 ◽  
Author(s):  
Frank AM Tuyttens

The algebraic relationships, underlying assumptions, and performance of the recently proposed closed-subpopulation method are compared with those of other commonly used methods for estimating the size of animal populations from mark-recapture records. In its basic format the closed-subpopulation method is similar to the Manly-Parr method and less restrictive than the Jolly-Seber method. Computer simulations indicate that the accuracy and precision of the population estimators generated by the basic closed-subpopulation method are almost comparable to those generated by the Jolly-Seber method, and generally better than those of the minimum-number-alive method. The performance of all these methods depends on the capture probability, the number of previous and subsequent trapping occasions, and whether the population is demographically closed or open. Violation of the assumption of equal catchability causes a negative bias that is more pronounced for the closed-subpopulation and Jolly-Seber estimators than for the minimum-number-alive. The closed-subpopulation method provides a simple and flexible framework for illustrating that the precision and accuracy of population-size estimates can be improved by incorporating evidence, other than mark-recapture data, of the presence of recognisable individuals in the population (from radiotelemetry, mortality records, or sightings, for example) and by exploiting specific characteristics of the population concerned.


2016 ◽  
Vol 852 ◽  
pp. 1319-1324 ◽  
Author(s):  
Jing Li ◽  
Chang Ping Wei ◽  
Feng Ming Wang ◽  
Li Dan Dong ◽  
Shuang Sun ◽  
...  

In this paper,under alkaline conditions,with chloroacetic acid to modify chitosan,obtained carboxymethyl chitosan. At pH<7 conditions,the obtained carboxymethy chitosan respectively were reacted with calcium chloride solution,zinc chloride solution,after fully reacted,obtained carboxymethyl chitosan calcium and carboxymethyl chitosan zinc .Through infrared spectrum,X-ray diffraction and scanning electron microscopy (sem) analysis means,the structure of the products were characterized.Through the cutting of mice tail hemostasia test ,study the performance of the product.The results showed that the water solubility of carboxymethyl chitosan is better than that of chitosan and with excellent performance,and the performance of carboxymethyl chitosan calcium and carboxymethyl chitosan zinc was better than that of carboxymethyl chitosan.


PEDIATRICS ◽  
1976 ◽  
Vol 57 (4) ◽  
pp. 474-479
Author(s):  
Robert B. Elliott

Seven children with cystic fibrosis (CF) have been treated for at least one year with intravenously administered soya oil emulsion. In all, an improvement of at least one biochemical abnormality in character with the disease appeared. The children's clinical course remains benign. This course is remarkably better than that of other children with CF treated without Intralipid in Auckland in the same period, though a placebo effect cannot be discounted. It is postulated that intravenous supplementation with essential fatty acid in CF may in turn partially correct an error of metabolism of prostaglandins present in the disease.


2016 ◽  
Vol 4 (4) ◽  
pp. 28
Author(s):  
Sabri Braha ◽  
Petrit Rama

The purpose of this research is to determine the impact of the turf-only substrate and turf–perlite in the ratio 2:1 and of growth regulators in the quality of adventive roots ( the number and length) of well lignified one-year old branches without fruit buds in the Bluecrop cultivar (Vaccinium corymbosum L.) taken at the end of the latent period before budding at the February 15 th during the -2015 growing season. In order to support the increase of the number of roots and their length the hardwood cuttings are treated with different IBA and NAA concentrations (1500, 3000, 4500 ppm), while a part of cuttings were untreated control. The number and the length of roots have increased in relation to the increase of concentration from 1500 to 3000 ppm followed by a decline of these values in concentrations over 3000 ppm. Respectively, the number of roots (8) and the higher values of root length (4.6 cm) are achieved in the turf–perlite substrate, IBA 3000 ppm (compared to the turf-only substrate). The presence of perlite helps the aeration of the substrate and supports biochemical and physiological processes which lead to the inducing of adventive roots. Regarding the number and length of roots an important variation for (p<0.05) was observed between different concentrations of IBA and NAA. In general the effect of IBA was a lot better than the effect of NAA.


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